Integrated structures can comprise stacks of integrated circuits or stacks of integrated circuits with interposers (i.e., interconnection supports). Interposers can also support several integrated circuits.
The mechanical stresses inside integrated structures can cause fractures or even delaminations separating several integrated circuits or supports that are assembled together. The mechanical stresses can be induced by stages in the manufacture of integrated circuits, and they can have an impact on performance of the products. The stresses therefore have a mechanical impact and an electrical impact within integrated structures. It is therefore advantageous to know the stress field values within structures.
It is possible to evaluate a unidimensional stress field using a resistor. On applying a mechanical stress to the resistor, a variation of the resistive value associated with the resistor appears and this variation is related to a sensitivity parameter. By way of indication, the variation of resistive values is equal to the product of the sensitivity value and the value of the unidimensional stress field.
Several identical resistors may be used to obtain bidimensional stress fields. However, it is not possible to obtain three-dimensional field values by using identical resistors placed on the same plane. Three-dimensional field values include, for example, components in a plane and components in a direction orthogonal to the plane.
To evaluate a three-dimensional stress field, it has been proposed to use a set of several resistors formed in silicon while using for at least one of the resistors a doping level that is different from that of the other resistors. However, this approach is complicated to implement and necessitates a large number of manufacturing stages.